EnglishViews: 150 Author: Site Editor Publish Time: 2020-09-02 Origin: Site
A transducer refers to a device that converts electrical energy and acoustic energy into each other. The converter that converts electrical energy into acoustic energy is called a transmitting transducer; the converter that converts acoustic energy into electrical energy is a receiving transducer. The main performance indicators of the transducer are operating frequency, frequency bandwidth, electro-acoustic frequency, the impedance at the resonance frequency, directivity (transmit beam width), and sensitivity. According to the physical characteristics and materials used, transducers can be divided into two categories: magnetostrictive transducers and electrostrictive transducers. The former uses the magnetostrictive effect of ferromagnetic materials, often made of nickel or nickel-iron alloys; the latter uses the electrostrictive and piezoelectric effects and is often made of dielectric materials such as barium titanate ceramics and milled lead titanate ceramics.
An ultrasonic transducer or ultrasonic sensor is an acoustic sensor. Ultrasonic transducers use piezoelectric ceramics that resonate at ultrasonic frequencies. The piezoelectric effect of the material converts electrical signals into mechanical vibration. Types of ultrasonic transducers: They can be divided into piezoelectric transducers, sandwich transducers, cylindrical transducers, inverted horn transducers, etc. When a voltage is applied to a piezoelectric transducer, the piezoelectric crystals change size and shape; AC voltage causes them to oscillate at the same frequency and generate ultrasonic waves.
The transducer consists of a housing, a matching layer, a piezoelectric ceramic disc transducer, a backing, a lead-out cable, and a Cymbal array receiver. The piezoelectric ceramic disc transducer is made of PZT-5 piezoelectric material polarized in the thickness direction. The Cymbal array receiver consists of 8 to 16 Cymbal transducers, two metal rings, and rubber gaskets.
Ultrasonic transducers are widely used. They are divided into industries, agriculture, and transportation, living, medical and military according to the industries they are applied to. According to the functions realized, it is divided into ultrasonic processing, ultrasonic cleaning, ultrasonic detection, detection, monitoring, telemetry, remote control, etc.; according to the working environment, it is divided into liquid, gas, living organisms, etc.; according to its nature, it is divided into power ultrasound, detection ultrasound, ultrasound imaging, etc.
Piezoelectric ceramic transducers use the piezoelectric effect of the polarized piezoelectric body to achieve voltage output. The input part is driven by a sinusoidal voltage signal, which causes it to vibrate through the inverse piezoelectric effect. The vibration wave is mechanically coupled to the output port through the input and output ports, and the output part generates electric charges through the positive piezoelectric effect to realize the two transformations of the piezoelectric body from electrical energy -mechanical energy-electrical energy. And obtain the highest output voltage at the resonant frequency of the piezoelectric transducer.
Compared with electromagnetic transformers, piezoelectric ceramic transformers have the advantages of small size, lightweight, high power density, and high efficiency, resistance to breakdown, high-temperature resistance, no fear of combustion, no electromagnetic interference and electromagnetic noise. In addition, the piezoelectric ceramic transformer has a simple structure, is easy to manufacture, and is easy to mass-produce, making it an ideal replacement component for electromagnetic transformers in some fields. Piezoelectric ceramic transformers are mainly used in switching converters, notebook computers, neon lamp drivers, etc.
The ultrasonic motor uses the stator as a transducer. The inverse piezoelectric effect of the piezoelectric crystal is used to place the motor stator at ultrasonic frequency vibration. Then the friction between the stator and the rotor transmits energy to drive the rotor to rotate. The ultrasonic motor has a small volume, large torque, high resolution, simple structure, direct drive, no brake mechanism, no bearing mechanism, these advantages are beneficial to the miniaturization of the device. Ultrasonic motors are widely used in optical instruments, lasers, semiconductor microelectronics processes, precision machinery and instruments, robotics, medicine, and biological engineering.
The principle of ultrasonic cleaning transducer is to use physical effects such as cavitation, radiation pressure, and sound flow when ultrasonic waves propagate in the cleaning solution, to peel off the dirt on the cleaning parts, and to promote the chemical reaction between the cleaning fluid and the dirt, last achieve the purpose of cleaning objects. The frequency used by the ultrasonic cleaning machine can be selected from 10 to 500 kHz according to the size and purpose of the cleaning object, generally 20 to 50 kHz. With the increase of the frequency of the ultrasonic transducer, Langzhiwan oscillator, longitudinal oscillator, thickness oscillator, etc. can be used. In terms of miniaturization, there are radial vibration and bending vibration of a wafer vibrator. Ultrasonic cleaning has been increasingly used in household equipment, electronics, automotive, rubber, printing, aircraft, food, hospital, and medical research industries.
There are two types of ultrasonic welding transducers: ultrasonic metal welding transducers and ultrasonic plastic welding transducers. Among them, ultrasonic plastic welding technology has been widely used. Ultrasonic welding uses the ultrasonic vibration generated by the transducer and transmits the ultrasonic vibration energy to the welding area through the upper welding piece. Due to the large acoustic resistance of the welding zone (that is, the junction of the two weldments), local high temperatures will be generated to melt the plastic or metal, and the welding work is completed under the action of contact pressure. Ultrasonic welding can easily weld parts that cannot be welded by other welding methods. In addition, it also saves expensive mold costs for plastic products, shortens processing time, improves production efficiency, and is economical, fast, and reliable.
By adding the fine abrasive with the ultrasonic processing tool to the workpiece under a certain static pressure, the same shape as the tool can be processed. During processing, the transducer needs to generate an amplitude of 15 to 40 microns at a frequency of 15 to 40 kHz. Ultrasonic tools make the abrasive on the surface of the workpiece subject to a continuous impact of considerable impact force, destroying the ultrasonic radiation site, breaking the material, and achieving the purpose of material removal. Ultrasonic processing is mainly applied to the processing of brittle and hard materials such as gems, jade, marble, agate, and cemented carbide, as well as the processing of shaped holes and fine deep holes. In addition, adding ultrasonic transducer vibration to ordinary cutting tools can also improve accuracy and efficiency.
Ultrasonic weight loss is to use the cavitation effect and micromechanical vibration of ultrasonic transducers to break down and emulsify excess fat cells under the human epidermis, and then excrete them to achieve the purpose of weight loss and shaping. This is a new technology developed internationally in the 1990s. Ultrasonic degreasing technology has achieved rapid development at home and abroad.
The ultrasonic transducer is used to receive the pressure of the blood vessel. When the balloon is pressurized and tightly pressed against the blood vessel, the ultrasonic transducer cannot feel the pressure of the blood vessel because the applied pressure is higher than the vasodilation pressure. When the pressure of the blood vessel decreases to a certain value, the pressure of the two reaches an equilibrium. At this time, the ultrasonic transducer can feel the pressure of the blood vessel. This pressure is the systolic pressure of the heart. The indicator signal is sent through the amplifier to give the blood pressure value. The elimination of the stethoscope on the electronic sphygmomanometer can reduce the labor intensity of the medical staff.
In toxic, radioactive and other harsh environments, people cannot work close to them and need to be controlled remotely; televisions, electric fans, and other electrical switches require a remote control. These can be equipped with ultrasonic transducers. By transmitting ultrasonic waves from a distance, the receiving transducer installed on the controlled system receives signals, converts the ultrasonic signals into electrical signals, and makes the switch act.
In modern transportation, it is necessary to automatically monitor the traffic and counting of vehicles in order to grasp the operation of the vehicles. For example, a traffic supervision station is equipped with an ultrasonic transducer and its auxiliary equipment that can be used for both transmission and reception. When the vehicle passes, there will be an acoustic pulse return. The number of daily vehicles can be obtained by counting and accumulating. Install a dual-use transducer at the rear of the car to prevent a rear-end collision. Installing a receiving piezoelectric ultrasonic transducer on the road can also monitor the noise figure.
The widespread use of ultrasonic transducers makes people's lives more and more convenient, and the quality of life is getting higher and higher. Weifang Jude is an ultrasonic transducers manufacturer and supplier specializing in providing ultrasonic transducers, providing ultrasonic cleaning transducers, ultrasonic welding transducers, and ultrasonic transducers.
